Concussion is often a difficult condition to diagnose. One diagnostic technique is the joint position error test, in which the ability of a subject, such as a patient, to return the head to an original orientation after rotating the head axially about the neck is measured. Typically, the test is administered in a subjective fashion, in which a clinician uses their judgment about the orientation of the subject's head, or otherwise mechanically measure the position of a subject's head to evaluate the results of the test.